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Please use this identifier to cite or link to this item: http://ir.ncue.edu.tw/ir/handle/987654321/18825

Title: 低維超導特性的研究
Study of Low Dimensional Superconductivity
Authors: 洪連輝;吳仲卿
Contributors: 物理學系
Keywords: 超導體;磁通蠕動;磁鬆弛現象;釘扎中心
High-Tc superconductor;Flux
creep
;Critical current density;Pinning center
Date: 1999
Issue Date: 2014-08-06T05:02:56Z
Abstract: 本計畫主要的目的在探討低維度的超導體特性,我們仔細地量測樣品在磁場下的磁鬆弛現象,其中磁化率對時間對數的關係,在兩個不同時段可分成兩種不同的磁鬆弛率,因此超導薄膜再磁場下的鬆弛現象可分為二維的pancake vortex和三維的column vortex,這兩種磁通的蠕動四度不同,故可決定二維與三維磁通在磁場對溫度關係的相轉變曲線,而這個邊界可就是三維磁通去耦合成二維磁通的相轉變。另外,我們也計算了由週期性陣列之釘扎中心所組成的樣品,若釘扎中心能量類似指數型態,我們計算磁通蠕動所產生的電阻,變換不同的釘扎中心的大小或距離,我們找到最佳化的釘扎中心大小。
The purpose of this study will investigate the mechanism of flux pinning for high-Tc superconductors. We assume a periodic array pinning centers in the superconducting thin films, which the potential energy of the pinning centers has a exponential form, and simulate to calculate the resistivity of flux creep. When we make a variation in the distance between pinning centers and the pinning size, we find the optimal pinning size which has minimal dissipative energy. Further, the resistivity of the samples with magnetic fields are measured under very low voltage in detail. Using the flux creep model, we can explain the data reasonably, and illustrate the magnetic field-temperature phase diagram.
Relation: 國科會計畫, 計畫編號: NSC88-2112-M018-005; 研究期間: 8708-8807
Appears in Collections:[物理學系] 國科會計畫

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